The benefits of pranayama for positive health are well known. Even though there are many studies published on the effectiveness of pranayama, there are very few papers that actually have systematically studied the physiological mechanisms involved, causing the benefits of pranayama, especially with respect to the cardiac function. This chapter attempts to have a detailed look at the physiology behind deep breathing. The chapter also conjectures that voluntary, deep breathing with attention may have a role to play in faster recovery from surgeries and prevent or delay the onset of Alzheimer's disease, Parkinson's disease, and maybe even cancer. Extended, carefully controlled, and detailed studies are needed to prove or disprove these conjectures.
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Indian tradition has always extolled the practice of different types of deep yogic breathing techniques, generally known as pranayama, for better health of a human being. Taylor et al. (2010) attempted a framework to integrate the mechanisms of the bidirectional interaction of mind and body that mediate efficacy of mind-body therapies. Telles et al. (2014) have proposed that yoga regulated breathing is a bidirectional mind-body practice. A number of studies (Pramanik et al., 2009; Dhungel et al., 2008; Russo et al., 2017) have shown reduction of heart rate and blood pressure after different types of pranayama practices. However, not many have looked into the physiological and neural mechanisms of how yoga breathing is intimately connected to the cardiovascular, chemoreflex and endocrine systems of the human body, thus leading to positive health, especially that of the heart. A variety of deep yoga breathing exercises are in practice, such as one involving a sound coming from a constricted throat (ujjayi), alternate nostril breathing (nadi shuddhi), forceful abdominal breathing (kapalabhati), cooling pranayama (sheetali), humming bee breathing (bhramari) and forced respiration with movement (bhastrika), which are performed at varying rates. In this article, the word pranayama is used in a very generic sense to denote a wide spectrum of many different types of deep yoga breathing practices and it needs to be emphasized that it clearly is not just one specific thing.
Fast and deep breathing is activated by the autonomic nervous system during strenuous exercises such as aerobic exercise, climbing a steep mountain or sprinting. This is because the increased muscle activity demands increased oxygen and the cells need more oxygen to burn more calories to release energy. However, interestingly, it is the brain, rather than the skeletal muscles, which consume more oxygen in general. Since many of human occupations today involve brain work, rather than physical work, it is important to delve deeper into the physiological and control mechanisms of voluntary, deep breathing and the role of the latter in ensuring efficient functioning of the brain.
This article carefully studies the respiratory physiology and the cardio-respiratory control circuits and identifies possible mechanisms behind the effect of yoga breathing in enhancing cardiac health (Ramakrishnan, 2019). In this article, deep yoga breathing refers to voluntarily taking deep breaths in a regular, systematic and near-periodic manner. It is proposed that voluntary, attentive, deep yoga breathing is a very effective cardiac exercise, while also having the potential to prevent many other ailments. While the article attempts to unravel some of the neural, physiological, chemical and hormonal connections, there may be other mechanisms playing a role in its effectiveness in assisting the overall health – including that of the brain. For example, Jerath et al. (2006) advance the hypothesis that only the stretch receptors are responsible for the effects observed.